Colorectal cancer (CRC) is the third most prevalent cancer worldwide and has poor prognosis. Recent improvement in methods for proteome analysis has offered the possibility of identifying disease-associated protein markers to assist in diagnosis or prognosis, and for selecting potential targets for specific drug therapy. In current study, the proteome of colorectal adenocarcinoma and the corresponding normal tissues was visualized and analyzed a number of proteins to isolate and identify tumor-specific proteins for CRC. Ten proteins were dominantly expressed and five proteins were largely repressed in CRC by the analysis of 2-DE and MALDI-TOF/mass spectrometry. Ubiquitin conjugating enzyme E2N, one of enzyme necessary for ubiquitination, and proteasome activator complex subunit 3 were focused to be increased in CRC tissues compared with normal colorectal tissues. The elevated expression of E2N and proteasome activator complex subunit 3 in CRC was confirmed by Western blot analysis and real time PCR. Immunohistochemistry also verified largely up-regulation of E2N and proteasome activator complex subunit 3 in 85 CRC patients. These findings suggest that ubiquitin conjugating enzyme E2N and proteasome activator complex subunit 3, which are involved in the ubiquitin-proteasome system, could be possible tumor biomarker candidates in CRC tissues. [Funding source: NRF grant (R13-2005-012-01003-0)].

Citation Format: Kee R. Kang, Jung H. Kang, Young-Tae Ju. Proteomic identification of ubiquitin conjugating enzyme E2N and proteasome activator complex subunit 3 as potential biomarkers in colorectal cancer tissues. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2484. doi:10.1158/1538-7445.AM2013-2484